Outpatient health emergency warning system

ABSTRACT

A medical system for sensing a physiological state requiring defibrillation in a patient. The system comprising: a low power sensor, a physiological parameter measuring device, and a processor. The low power sensor generating a baseline signal relating to a physiological status of said patient. The physiological parameter measuring device comprising at least one higher power sensor configured to output at least one physiological parameter signal indicative of at least one physiological parameter of said patient. The processor assessing the baseline signal and determining if the physiological status is outside predetermined threshold boundaries.

PRIORITY/CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.61/686,883, filed 13 Apr. 2012.

DESCRIPTION

FIG. 1 is a diagram of an embodiment of a medical system.

FIG. 2 is a diagram of a second embodiment of a medical system.

FIG. 3 is a diagram of am embodiment of a physiological parametermeasuring device.

FIG. 4 is a schematic representation of one embodiment of an opticalsensor.

FIG. 5 is a schematic representation of an LED driver.

FIG. 6 is a diagram illustration of one embodiment of a wrist wornmedical system.

FIG. 7 is a diagram illustration of another embodiment of a wrist wornmedical system.

FIG. 8 is a block diagram illustrating on embodiment of a master controlsystem.

The following description and the referenced drawings provideillustrative examples of the inventors' outpatient health emergencywarning system. As such, the embodiments discussed herein are merelyexemplary in nature and are not intended to limit the scope of theoutpatient health emergency warning system, or its protection, in anymanner. Rather, the description and illustration of these embodimentsserve to enable a person of ordinary skill in the relevant art topractice embodiments of the outpatient health emergency warning system.

The use of “e.g.,” “etc,” “for instance,” “for example,” and “or” andgrammatically related terms indicates non-exclusive alternatives withoutlimitation, unless otherwise noted. The use of “including” andgrammatically related terms means “including, but not limited to,”unless otherwise noted. The use of the articles “a,” “an” and “the” aremeant to be interpreted as referring to the singular as well as theplural, unless the context clearly dictates otherwise. Thus, forexample, reference to “a sensor” includes two or more such sensors, andthe like. The use of “optionally,” “alternatively,” and grammaticallyrelated terms means that the subsequently described element, event orcircumstance may or may not be present/occur, and that the descriptionincludes instances where said element, event or circumstance occurs andinstances where it does not. The use of “preferably” and grammaticallyrelated terms means that a specified element or technique is moreacceptable than another, but not that such specified element ortechnique is a necessity, unless the context clearly dictates otherwise.The use of “exemplary”, means “an example of” and is not intended toconvey a meaning of an ideal or preferred embodiment.

The use of “sensor” means any device that performs a measurement of itsenvironment and transmits a signal regarding that measurement, includingbut not limited to, capacitive sensors, proximity sensors, switches,buttons, sound/voice control sensors, RFID, infrared, accelerometers,and gyroscopes, unless the context clearly dictates otherwise.

The use of “motion sensor” means any device that measures motion andtransmits a motion signal, including but not limited to accelerometers,and gyroscopes, unless the context clearly dictates otherwise.

The use of “wireless connection” means any wireless signal, data,communication, or other interface including without limitation WiFi,Bluetooth, RF, ZIGBEE, ANT, acoustic, and infrared, unless the contextclearly dictates otherwise.

The use of “memory” means any type of long term, short term, volatile,nonvolatile, or other storage devices and is not to be limited to anyparticular type of memory or number of memories, or type of media uponwhich memory is stored, including but not limited to random accessmemory (RAM) or other dynamic storage device (e.g., dynamic RAM (DRAM),and static RAM (SRAM), synchronous DRAM (SDRAM), flash RAM), unless thecontext clearly dictates otherwise.

The use of “computer readable media” means any medium that participatesin providing instructions to a processor for execution, including butnot limited to hard disks, floppy disks, tape, magneto-optical disks,PROMs (EPROM, EEPROM, Flash EPROM), DRAM, SRAM, SDRAM, or any othermagnetic medium, magneto-optical disks, compact disks (e.g., CD-ROM),laser disc, digital versatile disc (DVD), Blu-ray disc, or any otheroptical medium, punch cards, paper tape, or other physical medium withpatterns of holes, a carrier wave (described below), or any other mediumfrom which a computer can read, and combinations of the above, unlessthe context clearly dictates otherwise.

The use of “control logic” applies to software (in which functionalityis implemented by instructions stored on a machine-readable medium to beexecuted using a processor), hardware (in which functionality isimplemented using circuitry (such as logic gates), where the circuitryis configured to provide particular output for particular input, andfirmware (in which functionality is implemented using re-programmablecircuitry), and also applies to combinations of one or more of software,hardware, and firmware, unless the context clearly dictates otherwise.

The use of “processor” means a programmable system including systems andmicrocontrollers, reduced instruction set circuits (RISC), applicationspecific integrated circuits (ASIC), programmable logic circuits (PLC),and any other circuit capable of executing the functions describedherein, including but not limited to microprocessors, digital signalprocessors, analog processors, analog devices (e.g., switchedcapacitors), analog/digital logic circuits, discrete transistors,integrated circuits, and many other devices can be used to perform suchprocessing, unless the context clearly dictates otherwise.

FIG. 1 illustrates a first medical system 10 for sensing a physiologicalstate requiring defibrillation in a patient, for instance asystole orventricular fibrillation. The medical system 10 having a low powersensor 12, physiological parameter measuring device 14, a master controlsystem 16, and alarm module 18.

The low power sensor 12 is for generating a baseline signal relating toa status of said patient, the baseline signal for initially predictingwhether or not the patient may be having cardiac problems. For instance,in one embodiment, the low power sensor 12 can comprise a motion sensor,such as an accelerometer, for sensing whether the patient has ceasedmovement, the motion sensor generating a motion signal relating to theactivity level of the patient. In another embodiment, the low powersensor 12 comprises an electrocardiogram (ECG) sensor for sensing theelectrical activity of the patient's heart over a period of time viaelectrodes attached to the surface of the patient's skin. Any suitablesensor may be utilized as the low power sensor 12.

The physiological parameter measuring device is 14 for measuring atleast one physiological parameter of the patient. The physiologicalparameter measuring device 14 comprising at least one physiologicalparameter sensor 15. Such a physiological parameter sensor 15 may havehigher power consumption than the low power sensor 12. In someembodiments, the physiological parameter sensor 15 has the ability to beplaced into a low power state, put to sleep, and be awakened by someevent, for instance by the low power sensor detecting a potentialexceptional condition is present.

The physiological parameter sensor 15 performs sensing operations. Toconserve battery power, when not performing sensing operations, thephysiological parameter sensor 15 sleeps or enters into another lowpower state (collectively referred to herein as a “low power state”). Insome embodiments, the control logic (discussed infra) can cause thephysiological parameter sensor 15 to enter into the low power state, forinstance, the master control system 16 can send a signal to thephysiological parameter sensor 15 instructing the physiologicalparameter sensor 15 to enter the low power state.

When the physiological parameter sensor 15 is not in the low powerstate, the physiological parameter sensor 15 acquires sensor data. Thephysiological parameter sensor 15 can analyze the sensor data todetermine whether an exceptional condition, such as a threshold beingexceeded, is present, and/or the physiological parameter sensor 15 canrelay the sensor data to another component, for instance the mastercontrol system 16, which can analyze the sensor data to determinewhether an exceptional condition, such as a threshold being exceeded, ispresent.

The physiological parameter sensor 15 is configured to output at leastone physiological parameter signal indicative of at least onephysiological parameter of the patient. The physiological parametersensor(s) can comprise any suitable physiological parameter sensor,including but not limited to ECG sensors, blood oxygen sensors, heartpulse sensors, pulse oximeters, and a temperature sensors. Thephysiological parameter measuring device 14 may comprise multiplephysiological parameter sensors located together in a central housing,for instance sensor 15 and sensor 17 illustrated in FIG. 1.

The physiological parameter sensor 15 is configured for placementadjacent the patient's skin interface, for allowing the physiologicalparameter sensor 15 to sense the patient's physiological status. In someembodiments, at least part of the physiological parameter measuringdevice 14 is disposed in a housing worn on at least one of the patient'swrists, or in a housing attached to a chest strap worn by the patient.Alternatively, the physiological parameter sensor 15 itself could beconfigured for wearing against the skin of the patient, for instance asa self-adhesive pad.

The master control system 16 is for controlling the operation of themedical system 10. The master control system 16 comprising a processor19 for assessing the baseline signal. The processor 19 implementing atleast in part control logic for determining if the patient'sphysiological status is below a threshold level or outside of certainnormal boundaries. Whereupon determining that the physiological statusmay be below said threshold level or outside of the boundaries, thecontrol logic is configured to wake up the physiological parametermeasuring device 14 and/or physiological parameter sensor 15 and/orphysiological parameter sensor 17 and/or other sensors. Upon waking up,the sensor 15 and/or sensor 17 acquiring a physiological parametersignal indicative of at least one physiological parameter of thepatient. In other embodiments, the processor and the sensor areintegrated together.

The processor 19 of the master control system 16 assessing the at leastone physiological parameter signal to determine whether a physiologicalstate requiring defibrillation in the patient is present. If it isdetermined that a physiological state requiring defibrillation in thepatient is present, the processor 19 outputs an alarm signal to alarmmodule 18.

The alarm module 18 for generating an alarm signal. The term alarmmodule including all devices usable with a medical system that aresuitable for giving an alarm or a warning, including but not limited toan amplifier and a speaker, a beeper, or another device capable ofmaking sound. The alarm signal may comprise an audible alarm indicatingto a third party, such as a medical or non-medical caretaker, that thepatient is experiencing emergency level physiological parameters and anexternal free-standing defibrillator needs to be utilized on saidpatient. The alarm module 18 can be worn by the patient, or can beremote from the patient. Further, a wireless connection can be utilizedto connect a remote alarm module to the medical system.

The medical system can further comprises an external, free-standingdefibrillator for use by a third party in response to said alarm.

The medical system could further comprise multiple physiologicalparameter measuring devices, each with one or more physiologicalparameter sensors. For instance, as illustrated in FIG. 2, a secondmedical system 20 for sensing a physiological state requiringdefibrillation in a patient is illustrated. The medical system 20 havinga first physiological parameter measuring device 21 including a lowpower sensor 26, and a master control system 28; a second physiologicalparameter measuring device 22; alarm module 27; a central receiverstation 29; and Emergency Medical Services 31.

The low power sensor 26 is integrated into the physiological parametermeasuring device 21, and is for generating a baseline signal relating toa status of said patient, the baseline signal for initially predictingwhether or not the patient may be having cardiac problems. For instance,in one embodiment, the low power sensor 26 can comprise a motion sensor,such as an accelerometer, for sensing whether the patient has ceasedmovement, the motion sensor generating a motion signal relating to theactivity level of the patient. In another embodiment, the low powersensor 26 comprises an electrocardiogram (ECG) sensor for sensing theelectrical activity of the patient's heart over a period of time viaelectrodes attached to the surface of the patient's skin. Any suitablesensor may be utilized as the low power sensor 26.

The first physiological parameter measuring device 21 and the secondphysiological parameter measuring device 22 are for measuring at leastone physiological parameter of the patient. In one embodiment, the firstphysiological parameter measuring device 21 and the second physiologicalparameter measuring device 22 each comprise at least one physiologicalparameter sensor (23, 24). In other embodiments, at least one of thephysiological parameter measuring devices may include multiplephysiological parameter sensors. The physiological parameter measuringdevices could include the same physiological parameter sensors, couldinclude some of the same physiological parameter sensors, or couldinclude none of the same physiological parameter sensors.

Such physiological parameter sensors 23, 24 may have higher powerconsumption than the low power sensor 26. In some embodiments, thephysiological parameter sensors 23, 24 have the ability to be placedinto a low power state, put to sleep, and be awakened by some event, forinstance by the low power sensor 26 detecting a potential exceptionalcondition is present.

As illustrated in FIG. 2, the first physiological measuring device 21and the second physiological measuring device 22, and the sensorsassociated therewith, are located separately, thereby enabling them tobe spaced apart if so desired. For instance, multiple physiologicalparameter measuring devices and/or sensors can be distributed on thepatient's body depending on the physiological parameter to be sensed(e.g., ECG electrodes).

The physiological parameter sensors 23, 24 perform sensing operations.To conserve battery power, when not performing sensing operations, thephysiological parameter sensors 23, 24 sleep or enter into another lowpower state (collectively referred to herein as a “low power state”). Insome embodiments, the control logic (discussed infra) can cause one orboth of the physiological parameter sensors 23, 24 to enter into the lowpower state, for instance, the master control system 28 can send asignal to one or both of the physiological parameter sensors 23, 24instructing it/them to enter the low power state. While in this Figurethe master control system 28 is illustrated as being integrated into thephysiological parameter measuring device 21, in other embodiments itcould be located within another module, or within a separate module.

When the physiological parameter sensors 23, 24 are not in the low powerstate, the physiological parameter sensors 23, 24 acquire sensor data.The physiological parameter sensors 23, 24 can analyze the sensor datato determine whether an exceptional condition, such as a threshold beingexceeded, is present, and/or the physiological parameter sensors 23, 24can relay the sensor data to another component, for instance the mastercontrol system 28, which can analyze the sensor data to determinewhether an exceptional condition, such as a threshold being exceeded, ispresent.

In some embodiments, the physiological parameter sensors 23, 24 are eachconfigured to output at least one physiological parameter signalindicative of at least one physiological parameter of the patient. Thephysiological parameter sensor(s) can comprise any suitablephysiological parameter sensor, including but not limited to ECGsensors, blood oxygen sensors, heart pulse sensors, a pulse oximeters,and a temperature sensors. The physiological parameter measuring devices21, 22 may comprise multiple physiological parameter sensors locatedtogether in a central housing.

In some embodiments, the physiological parameter sensors 23, 24 areconfigured for placement adjacent the patient's skin interface, forallowing the physiological parameter sensors 23, 24 to sense thepatient's physiological status. In some embodiments, at least part ofthe physiological parameter measuring device 21, 22 is disposed in ahousing worn on at least one of the patient's wrists, or in a housingattached to a chest strap worn by the patient. Alternatively, ate leastone of the physiological parameter sensors 23, 24 could be configuredfor wearing against the skin of the patient, for instance as aself-adhesive pad. In other embodiments, none of the components/modulesare worn on the patient's body.

The master control system 28 is for controlling aspects of the operationof the medical system 20. The master control system 28 in thisembodiment is integrated into the physiological parameter measuringdevice 21. The master control system 28 comprising a processor forassessing the baseline signal. The processor implementing at least inpart control logic for determining if the patient's physiological statusis below a threshold level. Whereupon determining that the physiologicalstatus may be below said threshold level, the control logic isconfigured to wake up at least one of the physiological parametermeasuring devices 21, 22, and/or at least one of the physiologicalparameter sensors 23, 24 and/or other sensors. Upon waking up, thephysiological parameter sensor(s) acquire a physiological parametersignal indicative of at least one physiological parameter of thepatient. In other embodiments, the processor and the sensor areintegrated together. In another embodiment, the master control system 28is integrated into the communication device 25 instead of thephysiological parameter measuring device 21, or another module.

In another embodiment, the master control system has an active mode, asleep mode, and an interrupt system. In such an embodiment, the mastercontrol system operates in a sleep (low power) mode until an interruptsignal is received, at which time the master control system “wakes up.”In one such embodiment, the master control system's default mode is thesleep mode. In sleep mode, the master control system utilizes lesspower. The low power sensor is configured to monitor the physiologicalstatus, and upon sensing a physiological status outside of boundaryconditions issue an interrupt signal to the master control system,triggering the master control system to enter into the active mode. Forinstance, in an embodiment including a motion sensor, such as anaccelerometer, when the patient's movements are above a certainthreshold, the accelerometer (or other module) could send an interruptsignal to the processor thereby interrupting the sleep mode. At thatpoint, the master control system can determine whether the physiologicalparameter is within normal limits, and if so can re-enter sleep mode. Ifthe physiological parameter is not within normal limits, the mastercontrol system could initiate other action.

In another embodiment, the master control system has an active mode, asleep mode, and an interrupt system. The low power sensor implementscontrol logic for determining if the physiological status is outsidepredetermined threshold boundaries. If the control logic determines thatthe physiological status is outside the threshold boundaries, thecontrol logic causes an interrupt signal to be issued to the mastercontrol system, triggering the master control system to enter into theactive mode.

The processor of the master control system 28 assessing the at least onephysiological parameter signal to determine whether a physiologicalstate requiring defibrillation in the patient is present. If it isdetermined that a physiological state requiring defibrillation in thepatient is present, the master control system 28 outputs an alarm signalto alarm module 27 and/or to communication device 25 (e.g., cell phone).

The alarm module 27 for generating an alarm signal. The alarm module 27can comprise an amplifier and a speaker, where the alarm signal is anaudible alarm indicating to a third party that the patient isexperiencing emergency level physiological parameters and an externalfree-standing defibrillator needs to be utilized on said patient.

The alarm module 27 and/or the master control system 28 can furthercomprise a communication device for communicating at least one of saidsignals to a central receiving station 29. The central receiving station29 could comprise an emergency level verification system for verifyingsaid signal(s) to determine if emergency level physiological parametersare present. The central receiving station 29 could further comprise aconfirmation signal generator for generating a confirmation signal uponthe verification of the presence of emergency level physiologicalparameters. The master control system 28 could be configured to receivethe confirmation signal and for automatically providing notice of thedetection of an emergency-level physiological parameter to a third partyproximal to the patient. The master control system 28 indicating to saidthird party that the individual is experiencing emergency levelphysiological parameters and the external free-standing defibrillatorneeds to be utilized on said individual. In some embodiments, thecentral receiving station 29 contacts emergency medical services 31regarding the emergency.

FIG. 2 illustrates the various components of the medical system 20wirelessly connected with one another. Alternatively, one or more of theconnections can be a wired connection. As illustrated in FIG. 2, awireless connection could be utilized enabling the components tocommunicate by radio through a small Personal Area Network (PAN) using aconvenient protocol. Such networks are known in the art and someexamples include, but are not limited to, the ZigBee protocol, the ANTprotocol, or Bluetooth. In some embodiments, the master control system28 could comprise a cell phone, or a fully custom wireless signalprocessing module as part of the PAN.

At least one of the physiological parameter sensors 23, 24 and/or atleast one of the physiological parameter measuring devices 21, 22 canpre-processes the physiological parameter signal for alarm levels,and/or can transmit pre-processed physiological data to a another modulefor further signal analysis. Preprocessing may include conversion of thephysiological parameter to an electrical signal, filtering, analog todigital conversion, digital filtering and other steps.

In the embodiment illustrated in FIG. 2, the physiological parametermeasuring device 21 comprises one or more sensors. Such sensorspotentially including, but not limited to, the low power sensor 26(e.g., a motion sensor), an IR pulse sensor, an ECG sensor, and atemperature sensor.

Upon detecting an alarm condition, the physiological parameter measuringdevice 21 and/or the master control system 28 can transmit an alertsignal, and optionally sample physiological data to communication device25 (e.g., a cell phone). The communication device 25 can transmit thealarm over a network, such as the cellular system, and through theInternet to a central receiver station 29. Upon detection of an alarmcondition, the central receiver station 29 can access patientinformation in a database and optionally dispatch Emergency MedicalServices 31, if needed.

In some embodiments, the signal processing steps are distributed amongthe various modules in the medical system.

In some embodiments, the physiological parameter sensors can eachtransmit pre-processed physiological data to the communication device25, which runs various algorithms to sense alarm levels in thephysiological parameters. The communication device 25 can sendphysiological or alert data to the central receiver station 29, therebydistributing at least some of the signal processing steps to separatedevices.

The medical system 20 includes an alarm module 27. Upon sensing an alarmcondition, a signal is received by the alarm module 27 prompting analarm. Examples of alarms include, but are not limited to, audio alarms,video alarms, audio/visual alarms, and message alarms transmittedremotely to a caregiver's electronic device (e.g., pager, cell phone).

FIG. 3 illustrates another embodiment of a physiological parametermeasuring device 40. This embodiment of a physiological parametermeasuring device 40 configured for wearing on the wrist of a patient,for instance as a watch or bracelet. One embodiment having a housingwith at least one strap or band extending therefrom. In the illustratedphysiological parameter measuring device 40, all of the sensors could becontained within a single housing.

The physiological parameter measuring device 40 illustrated in FIG. 3comprising an optical sensor 201, an ECG sensor 204, analogpre-processing module 205, touch switch 207, a low power sensor 209,temperature sensor 211, and processor 206.

The optical sensor 201 serves as a heart pulse sensor based on one ormore light emitting diodes (LEDs) and a photodiode somewhat similar towhat is used in a pulse oximeter. The optical sensor 201 can be used tosense blood oxygenation levels (SpO₂). One embodiment of an opticalsensor 201 comprises a light source 202 (e.g., a light-emitting diode(LED) module), light drivers configured for driving the LED(s) at anarrow constant current pulse, and photodiodes or in the alternative,phototransistors, which receive scattered light from the patient'stissue including blood. The amount of scattered light varies with tissueoxygenation resulting in received light amplitude which varies with thepatient's heartbeat. The photodiodes of transistors are connected to anamplifier which is designed to respond to narrow light pulses in orderto save power. The optical sensor 201 is adapted to determine whether aheart pulse is still present. In other words, during times ofventricular fibrillation, the pulse in the received light intensitywaveform will not be present and this absence is indicative absentperfusion such as in ventricular fibrillation, ventricular tachycardia,or other cases of cardiac arrest.

One component with a potentially significant current (power) draw is/arethe LED(s) used in the system. To produce useful light intensity, a LEDmust be driven with perhaps 10's of milli-amperes, a significant currentthat would quickly discharge a small battery. The battery drain problemcan be solved by scheduling the on time of the LED(s), both by drivingthe LED(s) with very narrow current pulses, and by optionally schedulingthe operation of the entire optical pulse detect system. For example, itis possible to detect heartbeats on a duty cycle basis such as fiveseconds on and fifteen to twenty seconds off. This would allow thedetection of about five heartbeats during the on time, and delay theworse case detection by only fifteen to twenty seconds. It is thereforepossible to extend battery life by minimizing on time of the LED(s).

In an embodiment worn on a patient's wrist, the optical sensor 201 canuse scattered light transmitted into the wrist from the bottom of thewrist worn portion (e.g., watch) of the device, or can use transmittedlight through the finger tip by means of a short cable connected to afinger clip. In the transmitted light case, the LED(s) and the opticalsensor 201 are on opposite sides of the fingertip while in the scatteredlight case the optical sensor and transmitter are on the same side ofthe wrist.

The physiological parameter measuring device 40 further comprising atemperature sensor 211. Such a temperature sensor 211 can be built intothe bottom of the housing to sense wrist temperature. Temperature sensor211 may comprise a programmable alarm function with both upper and lowertemperature alarm points, such as a Maxim DS18S20. In some embodiments,the temperature sensor 211 would have both low power operation, andautomatic operation unloading the processor 206 from background tasks,and allowing the processor 206 to maintain its lowest power mode for aslong as possible. Although temperature alone cannot be used to sensefibrillation, it is a commonly recorded physiological parameterphysicians often want to see if the device is used for physiologicalrecording. Similarly, the device and software can be extended so thatthe device can calculate SpO₂ and record physiological parameters suchas oxygen saturation values and heart rate in addition to being awarning device. In the SpO₂ case, multiple LEDs are used, both infraredand visible.

The ECG sensor 204 is for monitoring the electrical activity of thepatient's heart over a period of time. The ECG sensor 204 illustrated inthis Figure comprising an ECG amplifier 212, a first ECG electrode 203,a second ECG electrode 203′, and analog pre-processing module 205. TheECG amplifier 212 can be of conventional design, can be optimized forlow power use, for instance by utilizing micro-power operationalamplifiers where possible. The analog pre-processing module 205 caninclude filters to both keep the ECG baseline constant, andanti-aliasing filters for the A-D conversion step. While such aconfiguration of an ECG sensor is disclosed here, a skilled artisan willbe able to select an appropriate structure and configuration for an ECGsensor in a particular embodiment based on various considerations,including the intended use of the medical system, the intended arenawithin which the medical system will be used, and the equipment and/oraccessories with which the ECG sensor is intended to be used, amongother considerations.

The touch switch 207 has an interface 208. The touch switch 207 may beincorporated as a capacitive switch, such as a Rohm BU21010MUV. Acapacitive switch senses a finger touch, but is not mechanical foreasier waterproofing and operation. The touch switch 207 can be used tosense gestures, such as short touch, long touch, and finger motion,which can be used to both activate and inhibit alarms as alreadydescribed. Alternatively, touch switch 207 could comprise a touch screenon the front surface of the physiological parameter measuring device 40.

Low power sensor 209 can comprise a motion sensor, such as anaccelerometer having a low current operation, such as a Freescale MMA8450Q semiconductor. The motion sensor can have built-in motiondetecting features that run automatically, unloading the processor 206from background tasks.

In some embodiments, the low power sensor 209 includes automaticdetection of free-fall and transient detection, to detect a fall patternwhich would be a zero-G interval, the fall, followed by a transient, theimpact. Such a low power sensor 209 able to alert the processor 206and/or one or more of the other sensors to check for heart activity incase the fall is from cardiac arrest.

The motion sensor can perform two additional functions; during times ofextreme motion, the system can be placed into a lower power state byturning off the LEDs—a patient in ventricular fibrillation will not beexhibiting sustained extreme motion. It is also possible to use themotion sensor to sense convulsions that often occur during anoxia andcould mimic a heartbeat signal. Thus ventricular fibrillation can be alack of pulse and lack of motion, or a lack of pulse with a brief lackof motion followed by convulsion pattern then lack of motion again.Thus, the addition of the motion sensor saves power and extends batterylife and also increases the specificity of the physiological parametersensor.

The physiological parameter measuring device 40 may also comprise acommunication module 210 for allowing the physiological parametermeasuring device 40 to make a wireless connection with other devices.For instance, the communication module 210 may utilize the Bluetoothwireless technology standard and an antenna for exchanging data overshort distances with another device.

The physiological parameter measuring device 40 includes a processor206. The processor 206 connecting with the sensors, and containsalgorithms for detecting cardiac problems. Such algorithms are known inthe art, for example a method for detecting ventricular fibrillation(VF) from an ECG is disclosed in U.S. Pat. Nos. 4,184,493 and 4,475,551by Langer. The method described in those patents can be implemented insoftware.

The optical sensor 201 can be asleep and be awakened by the lack ofmotion from the low power sensor 209 (e.g., accelerometer or othermotion sensor). As another example, the optical sensor 201 could beawakened by output of ECG electrodes 203 and/or 203′. The exact sequenceof sensors running and waking other is programmable and tailored to thespecific patient.

FIGS. 4 and 5 illustrate one embodiment of an optical sensor 201. InFIG. 4, the optical sensor's output is examined for heart beat pulses bya correlation method. During a training phase, a pulse template is builtby looking for peaks in the pulse waveform and averaging data pointsaround those peaks that meet certain criteria. The average template isstored in the device. After the training phase as data comes in from theoptical sensor, the data continues to be examined for peaks. Each peakis cross-correlated with the template to see if a beat is present andthe pattern is examined for intervals. An absence of detected beats, oran interval pattern that is not normal, will trigger an alarm. Thismethod has been chosen since correlation is very effective in detectinga signal in noise.

Referring now to FIG. 5, illustrated is an LED driver with aprogrammable current drive. Preferably, the current is set by aprogrammable resistor, such as Microchip MMM and a PIO pin of themicroprocessor. The preferable current drive would not require a DAC inthe microprocessor and would have a lower current. Proper selection ofthe operational amplifier allows it to operate at the negative rail atlow current. Thereby, the overall current draw is reduced to almost thatof the LED current. Also illustrated is a high-speed trans-conductanceamplifier used to change the photodiode current into a voltage for themicroprocessor's analog to digital converter. The JFET is included toallow even higher speed operation by bootstrapping. Thus, the LED driverand photo amplifier have been designed with very narrow light pulses inmind, thereby minimizing current draw.

As discussed above, one embodiment of the system comprises a wrist-wornhousing containing at least a portion of the components of the system,for instance the optical sensor. In other embodiments, the opticalsensor may be separate from the wrist-worn housing—for example, theoptical sensor could be incorporated in to a finger ring worn on apatient's finger and connected by a wire to the wrist-worn housing.

FIG. 6 illustrates an embodiment of a wrist worn medical system 401. Thewrist worn medical system 401 comprises a transparent window on the topand bottom surfaces. The top window allows the user to see informationdisplayed on a display 403, such as an OLED display. The bottom windowallows light to be transmitted into the skin 412. The transmitted lightbeam 409 is generated by LED 404. The light beam 409 enters thepatient's skin at the wrist, and interacts with blood in the tissue 410of the patient's skin. The scattered light 411 is detected by photodiode405. Light passing directly from the LED 404 to the photodiode 405 isprevented by optical barrier 408 which is placed as close as possible tothe bottom transparent window. As already discussed, the scattered lightintensity will contain a pulsatile component caused by variations inarterial blood in the tissue pool synchronized to the heartbeat.

All components can be mounted on a printed circuit board 402, includingan accelerometer 406. Some components, such as the LED and thephotodiode, may be mounted on the PCB surface facing the wrist wornmedical system 401 (bottom surface); while other components, such as thedisplay 403, may be mounted on the top surface. Not illustrated areother components and modules, e.g., the processor, can also be mountedon the PCB.

On the bottom surface of the wrist worn medical system 401, directlyexposed to the patient's skin is also mounted ECG electrode 407 whichprovides one signal to the ECG processing circuit. This ECG electrode407 is insulated from the wrist worn medical system 401 case and may becomposed of conductive plastic or in the alternative, a capacitiveelectrode. A capacitive electrode is one where a very thin insulatingfilm is placed on the electrode's surface facing the patient's skin andis known to those skilled in the art.

FIG. 7, illustrates another embodiment of the medical system 500. Themedical system 500 is illustrated as a wrist worn medical system 501.Light energy is being transmitted from the bottom of the wrist wornmedical system 501 was already discussed. On the top surface of thewrist worn medical system 501 is both the transparent window allowingvisualization of the display, and a cancel button area 502 of the topsurface which allows cancellation of the transmitted alarm if thepatient is conscious. The top surface cancel button area 502 may beimplemented as a touch screen.

Flexible wire 503 exits the wrist worn medical system 501 to connectwith and upper arm ECG electrode 504 attached to an arm band 505. ECGsignal are measured as a potential difference between two electrodes.Here, as discussed above, one electrode is on the bottom surface of thewrist worn medical system 501, while the other electrode is somewhereelse on the forearm or upper arm. The spacing between the electrodeswill affect the quality of the ECG signal with larger spacings providinga better ECG signal. Other ECG electrode placements are possible, suchas a separate ECG module worn on a chest strap.

The medical system also contains an audio alert device and a switch,preferably a capacitive switch, on the front face of the watch. If analert condition is sensed, the audio alert is optionally sounded beforethe actual alert is transmitted. The patient has the opportunity todelay or cancel the alert by engaging and holding the switch. If thealert is real, the patient will become unconscious and release theswitch and the event is transmitted normally. In a non-alarm condition,the switch can be pushed to initiate a manually triggered help request.The user presses on the switch area and after several seconds ofconstant activation the alarm is sent. The delay is provided to minimizeaccidental activation.

FIG. 8 is a block diagram illustrating on embodiment of a master controlsystem 802 upon which the medical system for sensing a physiologicalstate requiring defibrillation in a patient may be implemented. Themaster control system 802 may be any one of a microprocessor-basedsystem, a personal computer system, a work station computer system, alap top computer system, an embedded controller system, a digital signalprocessor-based system, a hand held device system, a patient wornsystem, a personal digital assistant (PDA) system, a wireless system, awireless networking system, etc. In the embodiments illustrated in theFigures, the master control system 802 is a microprocessor-based system.

The master control system 802 includes a bus 804 or other communicationmechanism for communicating information, and a processor 806 coupledwith the bus 804 for processing the information. The master controlsystem 802 may also include a main memory 808 coupled to bus 804 forstoring information and instructions to be executed by processor 806.The main memory 808 may be used for storing temporary variables or otherintermediate information during execution of instructions to be executedby processor 806. Master control system 802 may further include a readonly memory (ROM) 810 or other static storage device (e.g., programmableROM (PROM), erasable PROM (EPROM), and electrically erasable PROM(EEPROM)) coupled to bus 804 for storing static information andinstructions for processor 806.

The master control system 802 also includes input/output ports 830 tocouple the master control system 802 to external devices, such sensorsand ECG electrodes. Such coupling may include direct electricalconnections, wireless connections, networked connections, etc., forimplementing automatic control functions, remote control functions, etc.

The master control system 802 may be coupled via bus 804 to an outputdevice 814 (e.g., liquid crystal display (LCD), light emitting diode(LED) display, voice synthesis hardware, voice synthesis software,speaker) for displaying and/or providing information to a patient,health care provider, or other person. The output device 814 may becontrolled by a display card, graphics card, sound card, or othermodules.

The master control system 802 can include one or more input devices 816,including but not limited to push buttons, keyboards, and a cursorcontrol 818, such as a touch screen, for communicating information andcommand selections to the processor 806. Such command selections canalso be implemented via voice recognition hardware and/or softwarefunctioning as the input devices 816. The cursor control 818, forexample, is a mouse, a trackball, cursor direction keys, touch screendisplay, optical character recognition hardware and/or software, etc.,for communicating direction information and command selections toprocessor 806 and for controlling cursor movement on the output device814 (e.g., a display).

The master control system 802 performs a portion or all of theprocessing steps of the medical system in response to processor 806executing one or more sequences of one or more instructions contained ina memory, such as the main memory 808. In alternative embodiments,hard-wired circuitry may be used in place of or in combination withsoftware instructions. Thus, embodiments are not limited to any specificcombination of hardware circuitry and software.

The master control system 802 also includes a communication interface820 coupled to bus 804. Communication interface 820 provides a two-waydata communication coupling to a network link 822 that may be connectedto, for example, a local network 824. For example, communicationinterface 820 may be a network interface card to attach to any packetswitched local area network (LAN), or to a personal area network (PAN)using a convenient protocol, including but not limited to the ZIGBEEprotocol, the ANT protocol, and Bluetooth. Wireless links may also beimplemented via the communication interface 820. In any suchimplementation, communication interface 820 sends and receiveselectrical, electromagnetic or optical signals that carry digital datastreams representing various types of information.

Network link 822 typically provides data communication through one ormore networks to other data devices. For example, network link 822 mayprovide a connection to a computer 826 through local network 824 (e.g.,a LAN) or through equipment operated by a service provider, whichprovides communication services through a communications network 828.The master control system 802 can transmit notifications and receivedata, including program code, through the network(s), network link 822and communication interface 820.

Another embodiment is a medical system for sensing a physiological staterequiring defibrillation in a patient, the system comprising: a lowpower sensor, said low power sensor generating a baseline signalrelating to a physiological status of said patient; physiologicalparameter measuring device comprising at least one higher power sensorconfigured to output at least one physiological parameter signalindicative of at least one physiological parameter of said patient; aprocessor, the processor assessing the baseline signal, the processorimplementing at least in part a control logic for determining if thephysiological status is outside predetermined threshold boundaries,whereupon determining that the physiological status is outside saidthreshold boundaries, the control logic is configured to enable said atleast one higher power sensor to acquire a physiological parametersignal indicative of at least one physiological parameter of saidpatient; and the processor assessing the at least one physiologicalparameter signal to determine whether a physiological state requiringdefibrillation in a patient is present.

Alternatively, the low power sensor comprises a motion sensor, andwherein said baseline signal comprises a motion signal relating to anactivity level of the patient. Alternatively, whereupon determining thata physiological state requiring defibrillation in a patient is present,the processor outputs an alarm signal to an alarm module, alarm modulefor generating an alarm. Alternatively, the low power sensor comprisesan ECG sensor. Alternatively, the medical system further comprises anexternal, free-standing defibrillator for use by a third party inresponse to said alarm. Alternatively, the physiological parametersensor is selected from the group consisting of an ECG sensor, a bloodoxygen sensor, heart pulse sensor, a pulse oximeter, and a temperaturesensor. Alternatively, at least part of the physiological parametermeasuring device is disposed in a housing worn on at least one of thepatient's wrists, or in an housing attached to a chest strap worn by thepatient. Alternatively, the alarm module comprises an amplifier and aspeaker, and said alarm signal is an audible alarm indicating to a thirdparty that the patient is experiencing emergency level physiologicalparameters and an external free-standing defibrillator needs to beutilized on said patient.

Alternatively, the alarm module further comprises a communication devicefor communicating at least one of said signals to a central receivingstation; said central receiving station receiving said signal(s), saidcentral receiving station comprising an emergency level verificationsystem for verifying said signal(s) to determine if emergency levelphysiological parameters are present, said central receiving stationfurther comprising a confirmation signal generator for generating aconfirmation signal upon the verification of the presence of emergencylevel physiological parameters; and a notification device configured toreceive said confirmation signal, said notification device alsoconfigured for automatically providing notice of the detection of anemergency-level physiological parameter to a third party proximal tosaid individual, said notification device indicating to said third partythat the individual is experiencing emergency level physiologicalparameters and the external free-standing defibrillator needs to beutilized on said individual. Alternatively, the master control systemhas an active mode, a sleep mode, and an interrupt system, wherein saidlow power sensor implements a control logic for determining if thephysiological status is outside predetermined threshold boundaries,whereupon determining that the physiological status is outside saidthreshold boundaries, the control logic is configured to issue aninterrupt signal to the master control system, triggering the mastercontrol system to enter into the active mode.

In another embodiment, the medical system is for sensing a physiologicalstate requiring defibrillation in a patient, said system comprising: amotion sensor, said motion sensor generating a motion signal relating toan activity level of the patient; physiological parameter measuringdevice comprising at least one physiological parameter sensor configuredto output at least one physiological parameter signal indicative of atleast one physiological parameter of said patient; a processor, theprocessor assessing the motion signal, the processor implementing atleast in part a control logic for determining when the patient'sactivity level is below a threshold level, whereupon determining thatthe patient's activity level is below said threshold level, the controllogic is configured to wake up said at least one physiological parametersensor to acquire a physiological parameter signal indicative of atleast one physiological parameter of said patient; the processorassessing the at least one physiological parameter signal to determinewhether a physiological state requiring defibrillation in a patient ispresent, whereupon determining that a physiological state requiringdefibrillation in a patient is present, the processor outputs an alarmsignal to an alarm module; and said alarm module for creating an alarmupon receipt of an alarm signal.

Alternatively, the medical system further comprising an external,free-standing defibrillator for use by a third party in response to saidalarm. Alternatively, the physiological parameter sensor is selectedfrom the group consisting of an ECG sensor, a blood oxygen sensor, heartpulse sensor, a pulse oximeter, and a temperature sensor. Alternatively,at least part of the physiological parameter measuring device isdisposed in a housing worn on at least one of the patient's wrists, orin a housing attached to a chest strap worn by the patient.Alternatively, the alarm module comprises an amplifier and a speaker,and said alarm signal is an audible alarm indicating to a third partythat the patient is experiencing emergency level physiologicalparameters and an external free-standing defibrillator needs to beutilized on said patient.

Alternatively, the alarm module further comprises a communication devicefor communicating at least one of said signals to a central receivingstation; said central receiving station receiving said signal(s), saidcentral receiving station comprising an emergency level verificationsystem for verifying said signal(s) to determine if emergency levelphysiological parameters are present, said central receiving stationfurther comprising a confirmation signal generator for generating aconfirmation signal upon the verification of the presence of emergencylevel physiological parameters; and a notification device configured toreceive said confirmation signal, said notification device alsoconfigured for automatically providing notice of the detection of anemergency-level physiological parameter to a third party proximal tosaid individual, said notification device indicating to said third partythat the individual is experiencing emergency level physiologicalparameters and the external free-standing defibrillator needs to beutilized on said individual.

Alternatively, the medical system further comprises a housing and awrist strap connected to said housing, wherein said motion sensor, atleast one of said physiological parameter sensors, and said processorare located within said housing. Alternatively, the motion sensor is anaccelerometer.

Another embodiment comprises a method of sensing a physiological staterequiring defibrillation in a patient comprising: placing aphysiological parameter sensor in a low power state; utilizing a motionsensor to generate a motion signal relating to an activity level of thepatient; assessing the motion signal and determining if the patient'sactivity level is below a threshold level; whereupon determining thatthe patient's activity level is below said threshold level, waking upsaid physiological parameter sensor, said physiological parameter sensorsensing at least one physiological parameter signal indicative of atleast one physiological parameter of said patient; and assessing the atleast one physiological parameter signal to determine whether aphysiological state requiring defibrillation in a patient is present;and whereupon determining that a physiological state requiringdefibrillation in a patient is present, outputting an alarm signal to analarm module to create an alarm. Alternatively, the method furthercomprises in response to said alarm, applying an AED to the patient.

The foregoing detailed description provides exemplary embodiments of themedical system and method, and includes the best mode for practicing themedical system. The description and illustration of these embodiments isintended only to provide examples of the medical system and method, andnot to limit the scope of the medical system and its method, or itsprotection, in any manner.

What is claimed is:
 1. A medical system for sensing a physiologicalstate requiring defibrillation in a patient, said system comprising: alow power sensor, said low power sensor generating a baseline signalrelating to a physiological status of said patient; physiologicalparameter measuring device comprising at least one higher power sensorconfigured to output at least one physiological parameter signalindicative of at least one physiological parameter of said patient; anda processor, the processor assessing the baseline signal, the processorimplementing at least in part a control logic for determining if thephysiological status is outside predetermined threshold boundaries,whereupon determining that the physiological status is outside saidthreshold boundaries, the control logic is configured to enable said atleast one higher power sensor to acquire a physiological parametersignal indicative of at least one physiological parameter of saidpatient, and the processor assessing the at least one physiologicalparameter signal to determine whether a physiological state requiringdefibrillation in a patient is present.
 2. The medical system of claim1, wherein said low power sensor comprises a motion sensor, and whereinsaid baseline signal comprises a motion signal relating to an activitylevel of the patient.
 3. The medical system of claim 1, whereupondetermining that a physiological state requiring defibrillation in apatient is present, the processor outputs an alarm signal to an alarmmodule, alarm module for generating an alarm.
 4. The medical system ofclaim 3, further comprising an external, free-standing defibrillator foruse by a third party in response to said alarm.
 5. The medical system ofclaim 3, wherein said alarm signal is an audible alarm indicating to athird party that the patient is experiencing emergency levelphysiological parameters and an external free-standing defibrillatorneeds to be utilized on said patient.
 6. The medical system of claim 3,wherein said alarm module further comprises a communication device forcommunicating at least one of said signals to a central receivingstation; said central receiving station receiving said signal(s), saidcentral receiving station comprising an emergency level verificationsystem for verifying said signal(s) to determine if emergency levelphysiological parameters are present, said central receiving stationfurther comprising a confirmation signal generator for generating aconfirmation signal upon the verification of the presence of emergencylevel physiological parameters; and a notification device configured toreceive said confirmation signal, said notification device alsoconfigured for automatically providing notice of the detection of anemergency-level physiological parameter to a third party proximal tosaid individual, said notification device indicating to said third partythat the individual is experiencing emergency level physiologicalparameters and the external free-standing defibrillator needs to beutilized on said individual.
 7. The medical system of claim 1, whereinsaid low power sensor comprises an ECG sensor.
 8. The medical system ofclaim 1, wherein said higher power sensor is selected from the groupconsisting of an ECG sensor, a blood oxygen sensor, heart pulse sensor,a pulse oximeter, and a temperature sensor.
 9. The medical system ofclaim 1, wherein at least part of the physiological parameter measuringdevice is disposed in a housing worn on at least one of the patient'swrists, or in a housing attached to a chest strap worn by the patient.10. The medical system of claim 1, wherein said processor has an activemode, a sleep mode, and an interrupt system, wherein said low powersensor implements a control logic for determining if the physiologicalstatus is outside predetermined threshold boundaries, whereupondetermining that the physiological status is outside said thresholdboundaries, the control logic is configured to issue an interrupt signalto the processor, triggering the processor to enter into the activemode.
 11. A medical system for sensing a physiological state requiringdefibrillation in a patient, said system comprising: a motion sensor,said motion sensor generating a motion signal relating to an activitylevel of the patient; physiological parameter measuring devicecomprising at least one physiological parameter sensor configured tooutput at least one physiological parameter signal indicative of atleast one physiological parameter of said patient; a processor, theprocessor assessing the motion signal, the processor implementing atleast in part a control logic for determining when the patient'sactivity level is below a threshold level, whereupon determining thatthe patient's activity level is below said threshold level, the controllogic is configured to wake up said at least one physiological parametersensor to acquire a physiological parameter signal indicative of atleast one physiological parameter of said patient; the processorassessing the at least one physiological parameter signal to determinewhether a physiological state requiring defibrillation in a patient ispresent, whereupon determining that a physiological state requiringdefibrillation in a patient is present, the processor outputs an alarmsignal to an alarm module; and said alarm module for creating an alarmupon receipt of an alarm signal.
 12. The medical system of claim 11,further comprising an external, free-standing defibrillator for use by athird party in response to said alarm.
 13. The medical system of claim11, wherein said physiological parameter sensor is selected from thegroup consisting of an ECG sensor, a blood oxygen sensor, heart pulsesensor, a pulse oximeter, and a temperature sensor.
 14. The medicalsystem of claim 11, wherein at least part of the physiological parametermeasuring device is disposed in a housing worn on at least one of thepatient's wrists, or in a housing attached to a chest strap worn by thepatient.
 15. The medical system of claim 11, wherein said alarm modulecomprises an amplifier and a speaker, and said alarm signal is anaudible alarm indicating to a third party that the patient isexperiencing emergency level physiological parameters and an externalfree-standing defibrillator needs to be utilized on said patient. 16.The medical system of claim 11, wherein said alarm module furthercomprises a communication device for communicating at least one of saidsignals to a central receiving station; said central receiving stationreceiving said signal(s), said central receiving station comprising anemergency level verification system for verifying said signal(s) todetermine if emergency level physiological parameters are present, saidcentral receiving station further comprising a confirmation signalgenerator for generating a confirmation signal upon the verification ofthe presence of emergency level physiological parameters; and anotification device configured to receive said confirmation signal, saidnotification device also configured for automatically providing noticeof the detection of an emergency-level physiological parameter to athird party proximal to said individual, said notification deviceindicating to said third party that the individual is experiencingemergency level physiological parameters and the external free-standingdefibrillator needs to be utilized on said individual.
 17. The medicalsystem of claim 11, further comprising a housing and a wrist strapconnected to said housing, wherein said motion sensor, at least one ofsaid physiological parameter sensors, and said processor are locatedwithin said housing.
 18. The medical system of claim 11, wherein saidmotion sensor is an accelerometer.
 19. A method of sensing aphysiological state requiring defibrillation in a patient comprising:placing a physiological parameter sensor in a low power state; utilizinga motion sensor to generate a motion signal relating to an activitylevel of the patient; assessing the motion signal and determining if thepatient's activity level is below a threshold level; whereupondetermining that the patient's activity level is below said thresholdlevel, waking up said physiological parameter sensor, said physiologicalparameter sensor sensing at least one physiological parameter signalindicative of at least one physiological parameter of said patient; andassessing the at least one physiological parameter signal to determinewhether a physiological state requiring defibrillation in a patient ispresent; and whereupon determining that a physiological state requiringdefibrillation in a patient is present, outputting an alarm signal to analarm module to create an alarm.
 20. The method of claim 19, furthercomprising in response to said alarm, applying an AED to the patient.